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Type LGPG111
Digital Integrated Generator
Protection Relay
Features
● An optimum mix of generator
protection functions
● Applicable to a wide range of
generators
● User configurable scheme logic
● An alternative setting group
● Wide operative frequency range
● Display of measured values
● Fault, event and disturbance
recording
● Integral testing to aid
commissioning
● Remote serial communications
● Power-on diagnostics and selfmonitoring
● Eight optically isolated logic inputs
for monitoring external plant.
Introduction
The LGPG111 is a multi-function relay
which integrates a number of common
generator protection functions and
associated scheme logic into a single
relay case.
Models Available
LGPG111
Incorporating 14 separate generator
protection functions (see Figure 2).
2
Figure 1: Relay Type LGPG111
Application
The LGPG111 can be applied to a
wide range of generators. Each of its
protection functions can be enabled
or disabled to suit individual
requirements. This approach avoids
the need for application-specific relay
versions, and simplifies the tasks of
relay specification, evaluation and
project planning. The integrated
scheme logic eliminates much panel
engineering work by reducing the
need for auxiliary relays and
associated external wiring.
Contacts from external protection and
plant monitoring equipment can be
connected to any of the eight
optically-isolated inputs. This allows
external information to be
incorporated into the relay’s userconfigurable scheme logic.
The optically-isolated inputs and relay
outputs may be labelled in the
software for local or remote
monitoring.
These functions can be recorded in
the alarm and event recording
facilities.
The protection functions provided by
the LGPG111 relay are as shown in
Figure 2.
Functions
Generator differential (87G)
The generator differential function is
for the protection of phase to phase or
three-phase stator windings faults
which normally involve high fault
currents, so that fast fault clearance is
required. This function works on a per
phase basis and has a dual slope
bias characteristic as shown in Figure
3: the lower slope provides sensitivity
for internal faults, whereas the higher
slope provides stability under through
fault conditions, especially if the
generator CTs saturate.
Stator earth fault (51N)
The stator earth fault function is
current operated and can be typically
set to cover up to 95% of the stator
windings. It is generally used on
resistively earthed generators, but can
also be used to respond to current in
the secondary circuit of an earthing
transformer loaded with a resistor.
A time-delayed low set element and
an instantaneous high set element are
provided.
Neutral displacement (59N)
The neutral displacement function is
voltage operated and is used for
detecting stator winding earth faults
on generators which are earthed via
a distribution transformer. Two timer
output elements are provided.
Sensitive directional earth fault (67N)
When two or more generators are
connected in parallel directly to a
busbar, the sensitive directional earth
fault function is used to discriminate
between internal and external earth
faults. A dedicated single-phase CT
input is available for the operating
current, which can accept the residual
current from three line CTs or current
from a dedicated core-balance CT.
The polarising signal for the
directional decision is either the
voltage signal applied to the neutral
voltage VT input or the current signal
applied to the stator earth fault current
input.
The stator earth fault, neutral
displacement and sensitive directional
earth fault functions all have third
harmonic rejection built in by means
of a software filter.
Voltage dependent overcurrent (51V)
The voltage dependent overcurrent
function is used for system backup
protection and can trip the generator
circuit breaker, if a fault has not been
cleared by other protection after a
certain period of time. The voltage
dependent function can be either
voltage controlled or voltage
restrained.
When voltage controlled, the timing
characteristic is changed from a load
to a fault characteristic when the
voltage drops below a set level. It is
mainly used for generators connected
directly to the busbar.
87G
Generator differential
51N
59N
Stator earth fault
Neutral displacement
67N
Sensitive directional earth fault
51V
32R
Voltage dependent overcurrent
Reverse power
32L
46
Low forward power
Negative phase sequence
40
Field failure
27
59
Under voltage
Over voltage
81U
81O
Under frequency
Over frequency
60
Voltage balance
60
27
59
81U
81O
32R
32L
40
87G
51V
67N
46
51N
59N
Figure 2: Protection functions provided by LGPG111
Differential
current
Trip
Is1
Percentage
bias K2
Percentage
bias K1
No Trip
Is2
Maximum mean bias current
Figure 3: Generator differential bias characteristic
Current
pick-up
level
I>
Current
pick-up
level
I>
KI>
KI>
Vs
Voltage
level
Vs2
Voltage controlled mode
Vs1
Voltage
level
Voltage restrained mode
Figure 4: Voltage dependent overcurrent functions
When voltage restrained, the current
pick-up level is proportionally lowered
as the voltage falls below a set value,
producing a continuous variation of
timing characteristics. This is
applicable to generators connected to
the busbar, each via a step-up
transformer.
A voltage vector compensation feature
is also available to determine the HV
phase-phase voltage signals where a
Yd1 or a Yd11 step-up transformer is
used.
The timing characteristic can either be
definite time or IDMT.
The effects of the voltage level on the
current pick-up level for both functions
are shown in Figure 4.
3
Reverse power (32R) and low forward
power (32L)
Reverse power protection is used to
detect loss of the prime mover.
Low forward power protection can be
applied to steam turbine generators
where sequential shutdown is
preferable, under less urgent
operations, to avoid over-speeding.
Both are balanced conditions,
therefore a single phase measurement
is sufficient. For this function, the relay
calculates VIcosθ for the A-phase.
In order to provide the required
sensitivity, a special current input is
used for both of these functions.
A compensation angle setting is also
available to compensate for phase
error of the generator’s CT and VT
signals. A delayed drop-off timer is
included in the timing logic which acts
as an integrating timer. This allows
the relay to trip within the predetermined time delay, under
pulsating power conditions.
t
tMAX
K
tmin
I2>>
I2
Figure 5: Negative phase sequence tripping characteristic
X
R
–Xa
Negative phase sequence (46)
Negative phase sequence function is
for the detection of sustained
unbalanced load conditions.
Under such circumstances double
frequency eddy currents are induced
in the rotor of a generator and can
cause rapid overheating. The function
has a thermal replica curve which
simulates the effects of pre-fault
heating due to low levels of standing
negative phase sequence current I2.
When the I2 value is well above
threshold, the thermal replica
approximates to a
t = K/I22 characteristic, where K is
the generator’s per-unit current
thermal capacity constant in seconds.
The tripping characteristic is shown in
Figure 5.
When high values of K are selected
and the negative phase sequence
currents measured are near to the
threshold, the operating time may be
too slow. In this case, a maximum
time setting tMAX is available to
provide a safe trip time.
When I2 is high, the operating time
may become too fast and cause loss
of discrimination with other power
system protection under fault
conditions. To reduce this risk, the
inverse characteristic is provided with
4
Xb
Figure 6: Field failure protection characteristic
an adjustable minimum operating time
setting tMIN.
A separate thermal capacity constant
setting Kreset is also provided for use
when the generator is cooling, due to
a reduction in I2. This is to cater for
rotor components with differing
cooling time constants.
An independent alarm element with a
definite time output is available for
pre-trip warning purposes.
Field failure (40)
Severe loss of excitation caused by
field failure can cause a high value of
reactive current to be drawn from the
power system which can endanger
the generator. The field failure
protection provided by this relay is a
single phase impedance measuring
element with an offset mho
characteristic, as shown in Figure 6.
An integrating timing arrangement,
identical to that for the power
functions, is also provided. This allows
the relay to trip within the predetermined time delay even though
the impedance measurement may
temporarily fall outside the mho
characteristic, eg. under pole-slipping
conditions.
Under voltage (27) and over voltage
(59)
An under voltage element and a
2-stage over voltage element are
provided. They are primarily used for
backing up the speed control
governor and the automatic voltage
regulator. When severe over voltage
occurs, the high set of the over
voltage element can be set to provide
fast operation. Both elements are 3phase devices.
Under frequency (81U) and over
frequency (81O)
Two under frequency elements and
one over frequency element are
provided. The underfrequency
elements are used to detect
overloading of the generator caused
by various system disturbances or
operating conditions.
The overfrequency element is used to
back-up the speed control governor if
overspeeding occurs.
Voltage balance (60)
The voltage balance function is
provided to detect VT fuse failure.
It compares the secondary voltages of
two sets of VTs (or from two
separately fused circuits of a single
VT) and can be used to block possible
incorrect tripping of those protection
functions whose performance may be
affected by the apparent loss of
voltage such as when a VT fuse
ruptures.
Configuration
Integrating timer facility
Time integration is required for the
power function to allow for
reciprocating load conditions where
the measuring element may pick up
briefly and periodically. The same
feature is also provided for the field
failure function for pole-slipping
conditions. Time integration allows the
function to operate within its predetermined operating time.
To implement timing integration, an
additional delayed drop-off timer is
provided. Once the protection
measurement element has picked up,
the relay will operate after the set time
delay, provided that the time interval
when the element drops off is within
the setting of the delayed drop-off
timer tDO.
The protection scheme logic for a
generator set normally involves a
large number of protection functions
combined together to drive a few
common trip outputs. Some blocking
and interlocking logic may also be
required. In order to accommodate
different generator applications, the
scheme logic is flexible and
reconfigureable.
The LGPG111 scheme logic is in the
form of logic arrays with an
architecture commonly found in
programmable logic array devices,
having an internal AND-OR structure
shown in Figure 7.
The OR functions allow one or more
of the AND function outputs to control
each output relay, whilst the AND
functions provide blocking or
interlocking for two or more inputs, or
just a through connection for one
input. There are 32 inputs to the
scheme logic: 19 from the protection
functions, 8 optically-isolated inputs
and a selection of inverted inputs to
allow blocking logic to be created.
The scheme logic controls a total of
15 output relays and has 32
selectable AND functions.
Frequency tracking
The relay tracks the power system
frequency and continuously adjusts its
internal sampling clock to exact
multiples of the system frequency.
This provides correct measurements
and operation of the protection
functions during start-up and run-down
of the generator set when the
generator unit is operated at
abnormal frequency. The operating
frequency range is from 25Hz to
70Hz for the differential function and
from 5Hz to 70Hz for the other
protection functions.
The input and output matrices allow
the desired connections to be created.
Each intersection of the matrix
represents a programmable
interconnection. By designing the
appropriate interconnections and then
entering the information into the relay,
Timer held facility
Both the overcurrent function, the low
set element of the stator earth fault
function and the neutral displacement
function are provided with a timer
held facility. The purpose is to enable
faster clearance of recurrent
intermittent faults, for example, selfsealing insulation faults. This facility
allows the relay timer to hold its value
when the current drops off, provided
that the drop-off period is less than the
tRESET timer setting.
This adjustable reset facility also
enables closer co-ordination with
electromechanical induction disc
relays.
Scheme logic
From protection elements
and status inputs
Output matrix
AND
AND
AND
Input matrix
OR OR
OR
To output relays
Figure 7: Block diagram of the scheme logic
5
through the scheme logic settings, the
required tripping logic can be
configured.
The presence of the optically-isolated
inputs to the scheme allows external
devices such as rotor earth fault relay,
temperature sensing devices and
mechanical relays to be connected to
the scheme, so that the tripping
facilities, together with the alarm and
remote communication facilities, can
be utilised.
The optically-isolated inputs and relay
outputs used in a scheme may be
allocated to any function required by
the application. The relay has a
facility to label each of these by
providing an identifier. The identifiers
are used during the configuration of
the scheme logic, by the input and
output status displays and by the
event, fault and disturbance recording
systems.
Alternative setting group
The relay provides an alternative
setting group which consists of all the
protection and scheme logic settings.
It can be used during start-up or rundown of generators or during
changes in power system
configuration. This setting group can
be selected by either energising the
appropriate optically-isolated inputs,
or via the relay settings menu.
Ancillary Functions
Measurements
The magnitudes of all 17 analogue
inputs to the relay are available for
display. Other derived quantities are
also available. This provides such
information as the three-phase,
residual and earth currents, the phase
to phase voltages, differential and
bias currents, negative phase
sequence current, phase A active and
reactive power plus the phase angle
and power system frequency.
All measurements can be displayed in
either primary or secondary
quantities, selectable by the user.
Primary display quantities are based
on the settings for the CT and VT
ratios used by the relay.
Event and fault records
Up to 100 event records are
available, all of them stored in nonvolatile memory. The latest record will
automatically overwrite the oldest
one. Event records are generated
whenever there is a protection
function operation, energisation of a
status input, operation of an output
relay or any hardware failure.
Fault records are also stored as
events. Out of the 100 event records,
up to 50 fault records can be
accommodated. Fault records are
initiated when user selected relay
outputs operate. The record consists of
the date and time of the fault, the state
of the optically-isolated inputs, relay
outputs and protection functions,
together with the measurement values
during the fault.
Disturbance records
The internal disturbance recorder can
store up to eight analogue channels,
together with all the status input and
relay output information.
The analogue channels are user
selectable from the relay’s 17 inputs.
The data in the analogue channels
can be stored as either raw data or as
magnitude and phase data. The raw
data is sampled at 12 samples per
electrical cycle, whereas the
magnitude and phase data are
calculated once every 20ms. Thus the
duration of a record varies with the
data type. For raw data, the duration
6
is 64 electrical cycles, but for
magnitude and phase data, the
duration is 7.68s. The latter set-up
allows long duration events such as
pole-slipping to be captured. In either
case, each data entry is time
stamped. This is particularly useful for
the raw data recording, since the
sampling interval varies with the
power system frequency, due to the
frequency tracking.
The disturbance recorder can be
triggered from selected relay outputs
and status inputs. A maximum of two
records can be stored in volatile
memory. A record remains in the
buffer area until it is uploaded to a
PC, after which the buffer is released.
If the two buffers are full, no further
recording can be made.
Time synchronisation
The clock for event record time
tagging has a resolution of 1ms.
To provide time synchronisation with
other equipment in the generator
station, the clock can be synchronised
by external clock pulses (0.5, 1, 5,
10, 15, 30 or 60 minute period) from
an optically-isolated input.
Print functions
Several print functions are provided to
allow the relay to provide hard-copy
documentation, via the front panel
parallel port. This consists of the
system settings, protection settings,
scheme logic settings, event records
and fault records. The scheme logic
print-out is formatted so that it can be
compared directly with the scheme
logic diagram.
Test features
A number of features are provided to
enable the relay to be thoroughly
tested during commissioning, routine
maintenance and fault finding
operations:
● The measurement functions allow
the analogue input and its
associated wiring to be checked.
● Display the on/off states of the
status inputs and relay outputs.
● Testing the four indicating LEDs.
● Testing the relay outputs and their
associated circuits by operating
the relay output contacts.
● Display the operation of each
protection function as a
percentage of the time-to-trip.
This allows the pick-up, progress
and operation of each protection
function to be checked.
● Testing the set-up of the scheme
logic settings by manually entering
an input pattern to the scheme,
and then examining its logical
output. This test can be performed
at any time without interfering with
the relay’s operation.
Power-on diagnostics and self
monitoring
Power-on diagnostic tests are carried
out by the relay when it is energised.
These tests include checks on the
timer, microprocessor, memory and
the analogue input module.
Continuous self-monitoring, in the form
of watchdog circuitry, memory checks
and analogue input module tests, is
also performed. In the event of a
failure, the relay will either lock-out or
attempt a recovery, depending on the
type of failure detected.
Hardware Description
Two relay output modules are
provided; each module contains 8
miniature relays. All relays are selfreset. However, a software function is
available which allows the user to
select outputs to be latched when
operated.
The relay is housed in a 4U (178mm)
high case suitable for either rack or
panel mounting. Internally, it consists
of a number of plug-in modules which
are individually tested and calibrated.
The modular hardware architecture is
shown in Figure 8.
The front panel consists of a 2 x 16
character alphanumeric liquid crystal
display (lcd) and a 7 push-button
keypad. It provides local access to all
of the relay’s features. There are also
4 light emitting diodes for visual
indication of the relay’s status, a nonisolated IEC870 serial port for
connection to a PC, and a parallel
port for connection to a printer.
The microcomputer module consists of
a powerful 16-bit microcomputer
which controls all of the subsidiary
modules through a 64-way ribbon
cable called the I/O Bus.
The processor performs all of the
major software functions such as input
signal processing, protection
algorithms, scheme logic, relay output
controls and handling of the operator
interface.
At the rear of the relay, apart from the
normal DC supply and plant
connections, there is an isolated
IEC870 port and a K-Bus port for
permanent connection to a remote PC.
The analogue input module consists of
12 CTs, 5 VTs and 6 optically-isolated
inputs. The CTs and VTs are used to
isolate and condition the analogue
inputs from the main transformers
connected to the generator.
Their output signals are then
converted into digital data for further
processing.
The remote communications module
is responsible for handling the
communications protocol and for
controlling the three communication
ports.
In addition to the 6 optically-isolated
inputs on the analogue module, a
further 8 are provided by the status
input module, making a total of 14
optically-isolated inputs available to
the relay. 6 of these have pre-defined
functions, such as clock
synchronisation, setting group
selection, etc., which leaves 8 inputs
to be fed into the scheme logic.
All of the optically-isolated inputs
operate from an auxiliary supply
Vx(2), which is independent of the
main auxiliary supply Vx(1).
The ratings of Vx(1) and Vx(2) may be
different (See Technical Data).
Microcomputer
I/O bus
Power
supply
Relay
outputs
Remote
comms
Status
input
Analogue
inputs
Front
panel
Figure 8: Hardware architecture
7
User Interface
Front panel user interface
The features of the relay can be
accessed through a user-friendly menu
system. The menu is arranged so that
related items (menu cells) are grouped
into individual sections, each of which
is identified by a title. The user
navigates around the menu by using
the arrow keys, first to select a
particular section title and then to
select an item within it. The front
panel liquid crystal display is limited
to displaying one menu cell at a time.
Software is available with each KITZ
to provide access to the relays, to
read and change settings. Additional
software entitled Protection Access
Software and Toolkit is available to
give access to the event recorder,
together with other additional
functions.
Each relay is directly addressable via
the bus to allow communication with
the PC. It should be noted that
protection tripping and blocking
signals are not routed via the K-Bus.
Separate conventional wiring is used
for these functions.
Remote access user interface
The menu can be accessed via the
remote communications facility.
This allows all of the menu cells in a
section to be displayed on the screen
of a PC. Changes to the menu cell
can be made from the PC keyboard.
Relay interconnection
Three communication ports are
available: the front panel, nonisolated IEC870 port; the rear,
isolated IEC870 port; and the K-Bus
port. The IEC870 ports use RS232
signal levels and allow point-to-point
connection. It is applicable when
networking is not required or during
commissioning.
Alternatively, the relays can be
connected via a shielded, twisted pair
called K-Bus. Up to 32 relays may be
connected in parallel to the bus.
K-Bus can be connected through a
protocol converter, type KITZ, either
directly or via a modem, to the RS232
port of a PC. K-Bus is RS485 based
and runs at 64kbits/s. The K-Bus
connection is shown in Figure 9.
SK1
Figure 9: K-Bus terminals connection arrangement
8
27 and 81U
inhibit
51V timer
inhibit
51N timer
inhibit
B25
A7
B26 Vab
I —residual
A8
A23
B27
Ia—diff
A24
A25
B23
A26
A27
G5
A28
A17
G1
Ia—bias
G3
A18
A19
A22
A9
Ia—sensitive
Setting group
select
(Part)
Integrated
Generator
Protection Relay
G2
G8
Clock
synchronising
A10
A11
G10
A12
A13
G13
Ib
A14
A15
Ic
A16
A5
G15
G14
Logic input 10
G19
G18
Ie
A6
B19
G20
B20
G23
Ve
Logic input 12
G16
G17
Logic input 13
Relay 5
DC supply +
Vx(1) –
G21
G22
Rear
IEC870
port
(isolated)
G25
G26
G28
9
Figure 10: External connection diagram Type LGPG111 (typical scheme)
B8
B9
F8
Relay 9
F2
F7
Relay 10
Relay 7
Ia—diff,
Ia—bias,
Ib—diff,
Ib—bias,
Ic—diff,
Ic—bias,
87G Generator differential
Ia, Ib, Ic
51V Overcurrent
46 Negative phase sequence
40 Field failure (Ia)
81U Under frequency (Ia)
810 Over frequency (Ia)
F9
F11
B10
B11
LGPG111
(Part)
Integrated
Generator
Protection Relay
Relay 11
F10
F12
Ia—sensitive 32R Reverse power
32L Low forward power
F13
F15
Relay 12
F16
F19
F21
F23
Relay 14
F22
D16
D19
F24
D20
D23
F27
F25
Relay 15
F26
Ve
59N Neutral displacement
67N SDEF (polarising)
27 Under voltage
59 Over voltage
81U Under frequency
810 Over frequency
32R Reverse power (Vab)
32L Low forward power (Vab)
40 Field failure (Vab)
60 Voltage balance
Vab—comp 60
Vbc—comp
F28
D24
D27
51N Stator earth fault
67N SDEF (polarising)
Vab, Vbc
F20
D14
D15
Ie
I—residual 67N SDEF (operating)
Relay 13
F18
D10
D13
Voltage balance
(Comparison voltages)
H3
H4
D28
H13
Power
supply
failure
alarm
H5
H6
H14
Case
earth
Relay 6
G24
G27
F4
F17
Logic input 11
Relay 4
B6
B7
D6
D9
G12
Ia
F6
Logic input 7
Logic input 9
Relay 3
B4
B5
F14
G9
G11
F1
D2
D5
Relay 2
Relay 8
F3
Logic input 6
Logic input 8
Note: CT and VT assignments
F5
B2
B3
B12
D1
Relay 1
G4
G7
Phase rotation
B
Relay inoperative
alarm
G6
LGPG111
Ic—bias
C
B24 Vbc— comp
Ic—diff
A20
A21
A
B21
B22 Vab — comp
Ib—diff
Ib—bias
Setting group
select
A B C
B28 Vbc
B1
Notes:
1. (a)
(b)
CT shorting links make
before terminals disconnect.
Short terminals break before (a).
2. CT connections are typical only.
3. SCN = Screen connection for K-Bus.
2 TX
3 RX
1
7
signal ground
1
protective ground
K-Bus
port
2
SCN
4. The IEC870 port at the front panel is non-isolated
and has different connection arrangements.
5. Frequency tracking on Vab, Vbc and Ia only.
6. Logic inputs are rated at Vx(2).
7. SDEF = Sensitive directional earth fault.
10
Input 13
Input 12
Input 11
Input 10
Input 9
–Input 9
Input 8
–Input 8
Input 7
–Input 7
Input 6
–Input 6
60 VB Comp
–60 VB–Prot (Blocking)
60 VB–Prot
40 Field Failure
67N Sensitive Dir EF
59N–2 Neutral Disp
59N–1 Neutral Disp
51N>> Stator EF
51N> Stator EF
46>> NPS Trip
46> NPS Alarm
59 Over Voltage
27 Under Voltage
81U–2 Under Freq
81U–1 Under Freq
81O Over Freq
32L Low Forward Power
32R Reverse Power
51V Over Current
87G Generator Diff
Logic 0
Logic 1
Logic 2
Logic 3
Logic 4
Logic 5
Logic 6
Logic 7
Logic 8
Logic 9
Logic 10
Logic 11
Logic 12
Logic 13
Logic 14
Logic 15
Logic 16
Logic 17
Logic 18
Logic 19
Logic 20
Logic 21
Logic 22
Logic 23
Logic 24
Logic 25
Logic 26
Logic 27
Logic 28
Logic 29
Logic 30
Logic 31
Ouput Matrix
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
&
Input Matrix
EN
8ms pick-up, 8ms drop-off
Relays 3, 11
2ms pick-up, 2ms drop-off
Relays 4, 5, 6, 7,
12, 13, 14, 15
2ms pick-up, 8ms drop-off
Figure 11: Type LGPG111 scheme logic
Relay 1
Relay 2
Relay 3
Relay 4
Relay 5
Relay 6
Relay 7
Relays 1, 2, 8, 9, 10
Relay 8
Relay 9
Relay 10
Relay 11
Relay 12
Relay 13
Relay 14
Relay 15
Output Inhibited
Note: Speed of the relay outputs are:
EN
Technical Data
Ratings
Inputs
AC Current In
1A or 5A
AC Voltage Vn
100V to 120V
Auxiliary voltage Vx(1)
(Relay power supply)
Auxiliary voltage Vx(2)
(Optically isolated status input supply)
Nominal dc (V)
24/27
30/34
48/54
110/125
220/250
Operative range (V)
19.2 – 32.4
24 – 40.8
38.4 – 64.8
88 – 150
176 – 300
24/27
30/34
48/54
110/125
220/250
19.2 – 32.4
24 – 40.8
38.4 – 64.8
88 – 150
176 – 300
Note: Vx(2) may be different from
Vx(1)
Frequency Fn
50/60Hz
Burdens
AC Current
Generator differential
<0.05VA per input at In (for 1A relay)
<0.20VA per input at In (for 5A relay)
Voltage dependent overcurrent,
field failure and negative
phase sequence
Reverse and low forward power
Stator earth fault and
sensitive directional earth fault
<0.05VA per input at In (for 1A relay)
<0.22VA per input at In (for 5A relay)
<0.15VA at In (for 1A relay)
<0.30VA at In (for 5A relay)
<0.12VA per input at In (for 1A relay)
<0.25VA per input at In (for 5A relay)
AC Voltage
<0.005VA per input at Vn
DC auxiliary voltage (Vx(1))
DC auxiliary voltage (Vx(2))
15W quiescent, max. 34W operating.
Less than 0.32W on average per input
Transformer ratios
CT ratios
1:1 to 9999:1 in 0.01 steps
VT ratios
1:1 to 9999:1 in 0.01 steps
CT requirements
Generator differential
Biased differential
settings at Is1=0.05In,
k1=0%, Is2=1.2In,
k2=150%
Vk ≥ 50In (Rct + 2RL + Rr)
where maximum
through fault current
= 10 x In and
maximum X/R = 120
Vk ≥ 30In (Rct + 2RL + Rr)
where maximum
through fault current
= 10 x In and
maximum X/R = 60
Note: Minimum knee point voltage = 34V
11
Earth fault protection functions
Sensitive directional
earth fault, using three
residually connected
line CTs
Vk ≥ 6In (Rct + 2RL + Rr)
where maximum
X/R = 5 and
maximum earth fault
current = 1 x In
Sensitive directional
earth fault, using core
balance CT
Vk ≥ 6NIn (Rct + 2RL + Rr)
where maximum
X/R = 5 and
maximum earth fault
current = 2 x In
Stator earth fault
Vk ≥ 6NIn (Rct + 2RL + Rr)
Ancillary protection functions
Voltage dependent
overcurrent, field failure
and negative phase
sequence
Vk ≥ 20In (Rct + 2RL + Rr)
where Vk = Minimum current transformer knee-point voltage for stability
In = Relay rated current (1A or 5A)
Rct = Resistance of current transformer secondary winding (Ω)
RL = Resistance of a single lead from relay to current transformer (Ω)
Rr = Resistance of any other protection functions sharing the current
transformer (Ω)
N =
Maximum earth fault current
Core balanced CT or earth CT rated primary current
Note: N should not be greater than 2. The core balance CT or earth CT ratio
must be selected accordingly.
Power function
For settings >3% Pn
Use correctly loaded class 5P protection CT
For settings ≤3% Pn
Use metering class CT. See table below.
Metering CT class recommended for power setting less than 3%Pn
Reverse/low forward Power Setting
(%Pn)
0.2
0.4
Metering CT Class
0.1
0.6
0.8
1.0
0.2
1.2
1.4
1.6
1.8
2.0
0.5
2.2
2.4
2.6
2.8
3.0
12
1.0
Thermal withstand
Continuous withstand CT input
4 x In
VT input
400V
CT input
100A for 1s (In = 1A)
Short time withstand
400A for 1s (In = 5A)
Setting ranges
Generator differential
Basic differential current setting Is1
0.05In to 0.1In in 0.01In steps
Threshold for increase bias Is2
1In to 5In in 0.1In steps
Bias K1 (Ibias < Is2)
0% to 20% in 5% steps
Bias K2 (Ibias > Is2)
10% to 150% in 10% steps
Stator earth fault
Low set element:
Characteristic
Standard inverse/Definite time
Current setting Ie>
0.005In to 0.5In in 0.005In steps
Time multiplier setting TMS
0.05 to 1.2 in 0.05 steps
IDMT Operating characteristic
t=
Definite time setting t>
0.1s to 10s in 0.1s steps
Reset timer setting tRESET
0s to 60s in 1s steps
0.14
x TMS
(I/Ie>)0.02–1
High set element:
Current setting Ie>>
0.005In to 2In in 0.005In steps
Time setting t>>
0s to 5s in 0.1s steps
Neutral displacement
Voltage setting Ve>
1V to 25V in 1V steps
Timer 1 setting t1
0.5s to 5s in 0.5s steps
Timer 2 setting t2
1s to 10s in 1s steps
Timer 2’s reset timer t2RESET
0s to 60s in 1s steps
Sensitive directional earth fault
Operating current Ires>
0.005In to 0.02In in 0.005In steps
Polarising voltage Vp>
1V to 10V in 1V steps
Polarising current Ip>
0.005In to 0.02In in 0.005In steps
Relay characteristic angle RCA
–95° to 95° in 1° steps
Voltage dependent overcurrent
Functions
Voltage controlled/Voltage
restrained/Simple
Characteristic
Standard Inverse/Definite Time
Current setting I>
0.5In to 2.4In in 0.05In steps
Time multiplier TMS
0.05 to 1.2 in 0.05 steps
IDMT Operating characteristic
t=
Definite time setting t
0s to 10s in 0.1s steps
Reset timer setting tRESET
0s to 60s in 1s steps
0.14
(I/I>)0.02–1
x TMS
13
Voltage settings:
Vs (for voltage controlled)
20V to 120V in 1V steps
Vs1 (for voltage restrained)
80V to 120V in 1V steps
Vs2 (for voltage restrainted)
20V to 80V in 1V steps
K factor
0.25 to 1.00 in 0.05 steps
Voltage vector rotate
None or Yd
Current pick-up level
Voltage Controlled
Voltage Restrained
I>
for V> Vs
I>
KI>
for V≤ Vs
KI> +
for V > Vs1
I> – KI>
(V – VS2)
VS1 – VS2
KI>
for Vs1≥ V ≥ Vs2
for V < Vs2
Reverse power
Power setting –P>
0.2W to 8W in 0.05W steps
(for 1A relay)
1W to 40W in 0.25W steps
(for 5A relay)
Delayed pick-up timer t
0.5s to 10s in 0.5s steps
Delayed drop-off timer tDO
0s to 5s in 0.1s steps
Low forward power
Power setting P<
0.2W to 8W in 0.05W steps
(for 1A relay)
1W to 40W in 0.25W steps
(for 5A relay)
Delayed pick-up timer t
0.5s to 10s in 0.5s steps
Delayed drop-off timer tDO
0s to 5s in 0.1s steps
Compensation angle θcomp
(for both reverse and
low forward power)
–5° to +5° in 0.1° steps
Note: The power settings are single phase quantities.
Negative phase sequence trip element
Trip threshold setting I2>>
0.05In to 0.5In in 0.01In steps
Thermal capacity constant (heating) K
2s to 40s in 1s steps
Thermal capacity constant (cooling) Kreset 2s to 60s in 1s steps
2
Operating Characteristic
(under no pre-heating condition)
t=–
Maximum operating time tmax
500s to 2000s in 10s steps
Minimum operating time tmin
0.25s to 40s in 0.25s steps
K
I >>
loge 1– 2
I2>>2
I2
Negative phase sequence alarm element
14
Alarm threshold I2>
0.03In to 0.5In in 0.01In steps
Alarm timer setting t>
2s to 60s in 1s steps
Field failure
Mho offset –Xa
2.5Ω to 25Ω in 0.5Ω steps
(for 1A relays)
0.5Ω to 5Ω in 0.1Ω steps
(for 5A relays)
Mho diameter Xb
25Ω to 250Ω in 1Ω steps
(for 1A relays)
5Ω to 50Ω in 0.2Ω steps
(for 5A relays)
Delayed pick-up timer t
0s to 25s in 0.1s steps
Delayed drop-off timer tDO
0s to 5s in 0.1s steps
Under voltage
Voltage setting V<
30V to 110V in 1V steps
Timer setting t
0.1s to 10s in 0.1s steps
Over voltage
Voltage settings V> ,V>>
105V to 185V in 1V steps
Timer settings t>, t>>
0s to 10s in 0.1s steps
Under frequency
Frequency settings F1< ,F2<
40Hz to 65Hz in 0.05Hz steps
Timer settings t1, t2
0.1s to 25s in 0.1s steps
Over frequency
Frequency settings F>
40Hz to 65Hz in 0.05Hz steps
Timer settings t
0.1s to 25s in 0.1s steps
Voltage balance
Voltage setting Vs
5V to 20V in 1V steps
Digital Inputs
Optically isolated inputs
14 (6 dedicated, 8 available to the
scheme logic)
Contacts
Output relays
10 dual make
2 single make
3 change-over
Power supply failure alarm
1 single make
1 single break
Relay inoperative alarm
1 change-over
Contact rating
Make: 30A and carry for 0.2s
Carry: 5A continuous
Break: dc 50W resistive
25W inductive
(L/R = 0.4s)
ac 1250VA
Subject to maxima of 5A and 300V
Durability
Loaded contact
10,000 operations
Unloaded contact
100,000 operations
15
Communications
Language
Courier
IEC870 port (front/rear)
Transmission mode
Signal levels
Message format
Data rate
Connection
Cable type
Cable length
Connector
Isolation
Asynchronous
RS232
IEC870 FT1.2
600 – 19200 bits/s
Single-ended
Screened multi-core
15m
25-way D-type female
Front (non-isolated)
Rear (1kV rms for 1 minute to case
earth and other circuits)
K-Bus port
Transmission mode
Signal levels
Message format
Data rate
Connection
Cable type
Cable length
Connector
Isolation
Synchronous
RS485
HDLC
64 kbits/s
Multidrop (32 units)
Screened twisted pair
1000m
Screw terminals
2kV rms for 1 minute
Voltage withstand
Dielectric withstand
IEC255-5: 1977
Impulse voltage
IEC255-5: 1977
Insulation resistance
IEC255-5: 1977
2.0kVrms for 1 minute between all
terminals and case earth
2.0kVrms for 1 minute between
terminals of independent circuits,
including contact circuits
1.0kVrms for 1 minute across
open contacts of output relays
1.0kVrms for 1 minute between
IEC870 rear port and earth
5kV peak, 1.2/50µs, 0.5J between
all terminals and all terminals to
case earth
>100MΩ
Electrical environment
DC supply interruptions
IEC255-11: 1979
AC ripple on DC supply
IEC255-11: 1979
High frequency disturbance
IEC255-22-1: 1988
16
The relay shall withstand a 10ms
interrupt without de-energising
The relay will withstand 12% ripple
2.5kV first peak between
independent circuits and case
1.0kV first peak across terminals of
the same circuit.
No additional tolerances are
required for the operating time or
the relay’s thresholds
Electrostatic discharge test
IEC255-22-2: 1989
Fast transient disturbance
IEC255-22-4: 1992
Class III (8kV) – air discharge
Level 3 (6kV) – point contact
discharge (IEC801–2: 1991)
No additional tolerances are
required for the operating time or the
relay’s thresholds
Class IV (4kV, 2.5kHz)
Class III (2kV, 5kHz)
No additional tolerances are
required for the operating time or the
relay’s thresholds
Radio frequency interference
Radiated immunity
IEC255-22-3: 1989
Class III field strength 10V/m
Extended frequency range 20MHz to
1000MHz
Conducted immunity
IEC801-6: 1994
10V rms, 0.15MHz to 80MHz
Radiated emissions
EN55022: 1994
Class A
Conducted emissions
EN55022: 1994
Class A
EMC compliance
89/336/EEC
EN50081-2: 1994
EN50082-2: 1995
Product safety
73/23/EEC
EN 61010-1: 1993/A2: 1995
EN 60950: 1992/A3: 1995
Compliance with the European
Commission Directive on EMC is
claimed via the Technical Construction
File route. Generic Standards
were used to establish conformity
Compliance with the European
Commission Low Voltage Directive.
Compliance is demonstrated by
reference to generic safety standards.
Atmospheric environment
Temperature
IEC255-6: 1988
Humidity
IEC68-2-3: 1969
Enclosure protection
IEC529: 1989
Storage and transit -–25°C to +70°C
Operating –25°C to +55°C
56 days at 93% relative humidity
at 40°C.
IP50 (dust protected)
Mechanical environment
Vibration
IEC255-21-1: 1988
Vibration response Class 2
Vibration endurance Class 2
Shock and bump
IEC255-21-2: 1988
Shock response Class 2
Shock withstand Class 2
Bump Class 1
Seismic
IEC255-21-3: 1993
Class 2
17
Case
The relay is housed in a multi-module
MIDOS case as shown in Figure 12.
Additional Information
LGPG111 Service Manual
R5942
Courier Communications leaflet
R4113
Information Required with Order
Unit type:
LGPG111 01 S
Case mounting
Flush panel
Rack
1
2
Vx(1) auxiliary voltage
24V
30V
48V
110V
220V
1
2
3
4
5
Vx(2) auxiliary voltage
24V
30V
48V
110V
220V
1
2
3
4
5
CT rating
1A
5A
L
M
Language
English
French
German
Spanish
18
E
F
G
S
483mm Rack details
Dimensions to IEC 297
Rack mounting
7 max.
438
31.75
±0.4
12.7
±0.4
Removable
cover
432
450 min.
Hinged front
panel
Push button
projection 10mm max.
U Scale
U = 44.45
465.1 ±1.6
Tolerance between
any two holes
within a distance
of 1mm ±0.4
10
178
101.6
10
465
483
252
37
Side
Front
Allow a minimum of
50mm for terminal block
and wiring
10.6
7
Fixing hole detail
All dimensions in mm
Terminal screws:
M4 x 8 brass Cheese Head with
Lockwashers are provided
Panel mounting
Mounting screws are not provided
438
Panel cut-out detail
400
200
Removable
cover
432
Hinged front
panel
Push button
projection
10mm max.
180.5 191
10
440
178
201
Fixing holes
Ø5.4
10
443
Front
37
252
Side
Allow a minimum of 50mm for
terminal block and wiring
Figure 12: Case outlines
19